Battle of White Wolf Mountain

The Battle of White Wolf Mountain was fought from September to October 207 AD when Cao Cao and his army defeated the combined forces of Yuan Shang/Yuan Xi and the Wuhuan tribe at White Wolf Mountain in the Gobi Desert. Cao Cao's victory led to the brothers' deaths and his unification of the north of the north.

Background
In 205 AD, after the death of their brother Yuan Tan at the Battle of Nanpi, Yuan Shang and Yuan Xi retreated to You Province, and they later abandoned the province as Cao Cao's army neared. They fled to the Wuhuan, who agreed to ally with them against Cao Cao. In 207 AD, having subdued Bing Province at the Battle of Huguan Pass, Cao Cao ignored Cao Hong's advice to return to Xuchang and instead followed Guo Jia's advice to march into the Gobi Desert to destroy the barbarians, who had been allied to Yuan Shao for years. The expedition was difficult as the soldiers marched through oceans of yellow sand and fierce winds, and Guo Jia took ill from the conditions, returning to Yezhou for treatment as Yuan Shao's former general Tian Chou guided the advance of Cao Cao's army. After engaging in double marches, they reached the White Wolf Hills, where they faced Yuan Xi, Yuang Shang, and Mao Dun and a force of 10,000 cavalry.